Some Canadians began moving for independence from Great Britain. Some Americans helped the Canadians in their effort, which exacerbated tensions in the U.S.–Great Britain relationship. Canadian loyalists, with support from Great Britain, then seized an American ship named the Caroline, which contained supplies for Canadian rebels. During this seizure, American Amos Durfree was killed.

Van Buren ordered General Winfield Scott to the area to prevent further hostilities. He also issued a proclamation of neutrality, stating that the United States would remain neutral in the Canadian–British struggle.